Abstract: A method and a device for picking up seedlings from a seedling tray is capable of picking up seedlings by accurately arranging seedling storage cells in opposition to seedling pushing rods irrespective of the transporting tilt of the seedling tray. In the method, the seedling tray formed with a plurality of seedling storage cells is positioned at a predetermined position by means of tray positioning rods, and the seedling pushing rods are inserted into respective seedling storage cells while maintaining the positioned condition. The device implementing the method includes the tray positioning rods for positioning the seedling tray at the predetermined position and the seedling pushing rods for performing an inserting operation for respective seedling storage cells while maintaining the positioned condition of the seedling tray by the tray positioning rods.

Abstract: Disclosed herein is a magnetic tape unit having a magnetic head for reading and writing data from and onto a magnetic tape. The magnetic tape is traveled in contact with the magnetic head during a read/write operation of the magnetic head. During a rest period where the read/write operation of the magnetic head is not performed, a reciprocating motion of the magnetic tape by a small distance is performed with a predetermined period. A temperature in the vicinity of the magnetic head is detected by a temperature sensor. The predetermined period is changed according to the temperature detected by the temperature sensor. Accordingly, the adhesion of the magnetic tape to the magnetic head can be well prevented irrespective of the temperature inside the tape unit.

Abstract: An oscillator actuated hydraulic impulse of the type including a spool valve actuated by an alternating signal from an oscillator to switch the hydraulic pressure in a double acting cylinder in order to cause reciprocating motion of a piston which strikes a boring tool. The hydraulic impulse device further includes a means for controlling the transition from the impulse stroke to the return stroke of the piston. In some embodiments, the hydraulic impulse device may further include a means for varying the duration of the impulse stroke and the return stroke of the piston.

Abstract: A hydraulic hammer wherein the reciprocal motion of a drill-striking piston is operated by means of a spool valve for switching hydraulic pressure to a double-acting cylinder depending upon the position of the piston. The hydraulic hammer further includes a self starter means which assures activation of the hammer whenever hydraulic pressure is applied to the hydraulic hammer and a means for compensating for variations in boring conditions such that energy is efficiently delivered by the drill striking piston.